Antimicrobial phase-separable glass/polymer composite articles and methods for making the same

ABSTRACT

A method of making an antimicrobial composite article, including the steps: providing a matrix comprising a polymeric material; providing a plurality of second phase particles comprising an antimicrobial agent; melting the matrix to form a matrix melt; distributing the plurality of second phase particles in the matrix melt at a second phase volume fraction to form a composite melt; forming a composite article from the composite melt; and treating the composite article to form an antimicrobial composite article having an exterior surface comprising an exposed portion of the matrix and the plurality of second phase particles. The distributing step can employ an extrusion process. The forming a composite article step can employ an injection molding process. The treating step can employ abrading and plasma-treating the article to define the exterior surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/769,943 filed on Apr. 20, 2018, which claims the benefit of priorityunder 35 U.S.C. § 371 of International Application No.PCT/US2016/057804, filed on Oct. 20, 2016, which claims the benefit ofpriority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No.62/244,368 filed on Oct. 21, 2015, the content of each of which isrelied upon and incorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates generally to antimicrobial compositearticles and methods for making them. More particularly, the variousembodiments described herein relate to glass/polymer compositeantimicrobial articles having copper-containing antimicrobial agents andvarious methods for making them.

Consumer electronics articles, including touch-activated ortouch-interactive devices, such as screen surfaces (e.g., surfaces ofelectronic devices having user-interactive capabilities that areactivated by touching specific portions of the surfaces), have becomeincreasingly more prevalent. As the extent to which the touchscreen-based interactions between a user and a device increases, so toodoes the likelihood of the surface harboring microorganisms (e.g.,bacteria, fungi, viruses, and the like) that can be transferred fromuser to user. Moreover, the housings which incorporate thetouch-activated or touch-interactive devices also include surfaces thatharbor such microorganisms that can be transferred from user to user.The concern of microorganism transfer is also a concern with many “hightouch” surfaces associated with various electronic equipment, furnitureand architectural articles, counter-tops, table-tops, control panels andother articles used in medical, office and consumer settings in whichusers, consumers or the like come into contact with these surfaces.

To minimize the presence of microbes on various materials, so-called“antimicrobial” properties have been imparted to a variety of glasses;however, there is a need to provide entire articles (including thehousing and any glasses used as cover glass) that also exhibitantimicrobial properties. Accordingly, antimicrobial articles useful forcertain applications should be durable enough for the purpose for whichthey are used, while also providing continuous antimicrobial propertiesthat are passive or do not require additional activation by a user oroutside source (e.g., UV light). In addition, antimicrobial glasses andarticles should provide controlled antimicrobial activity.

In some situations, polymer/glass composite articles intended to exhibitantimicrobial properties demonstrate far less antimicrobial efficacy.One problem associated with such articles is ensuring that theantimicrobial agents are present at the surfaces of these articles at aconcentration sufficient to provide the desired antimicrobial efficacy.Another problem is ensuring that the microbes present on the surfaces ofsuch article are in residence for a sufficient duration to be killed orneutralized by the antimicrobial agents within the composite articles.

Accordingly, there is a need for antimicrobial composites articlespossessing exterior surfaces that can be configured to produce desiredantimicrobial efficacy levels, along with processes for making the same.

SUMMARY

A first aspect of the present disclosure pertains to an antimicrobialcomposite article that includes: a matrix comprising a polymericmaterial; and a plurality of second phase particles comprising aphase-separable glass with a copper-containing antimicrobial agent. Theplurality of particles is distributed within the matrix at a secondphase volume fraction. Further, the composite article defines anexterior surface comprising an exposed portion of the matrix and theplurality of the second phase particles.

The second phase particles of the antimicrobial composite article insome aspects can include phase-separable glass that includes at leastone of B₂O₃, P₂O₅ and R₂O, and the antimicrobial agent is cuprite whichincludes a plurality of Cu¹⁺ ions. In certain aspects, the plurality ofsecond phase particles has a size distribution defined by a 325 standardUS mesh size. Further, the phase-separable glass can comprise betweenabout 10 and 50 mol % cuprite.

The matrix of the antimicrobial composite article in some aspects caninclude a polymeric material selected from the group consisting of apolypropylene, a polyolefin and a polysulfone. In certain aspects, thepolymeric material can be characterized by substantial hydrophobicity,while the exposed portion of the matrix is characterized by substantialhydrophilicity. Other aspects of the antimicrobial composite articleemploy a matrix with a polymeric material characterized by substantialhydrophilicity (e.g., within its bulk and on its exposed surfaces andportions). In addition, the exposed portion of the matrix can comprisefunctional groups derived from a plasma treatment of the matrix.

In some implementations of the antimicrobial composite article, theexterior surface of the article exhibits at least a log 2 reduction in aconcentration of at least one of Staphylococcus aureus, Enterobacteraerogenes, and Pseudomonas aeruginosa bacteria under modified UnitedStates Environmental Protection Agency “Test Method for Efficacy ofCopper Alloy Surfaces as a Sanitizer” testing conditions, wherein themodified conditions include substitution of the antimicrobial compositearticle with the copper-containing surface prescribed in the Method anduse of copper metal article as the prescribed control sample in theMethod (collectively, the “Modified EPA Copper Test Protocol”). Incertain aspects, the exterior surface can exhibit at least a log 3, log4, or even a log 5, reduction of the same bacteria under the sameModified EPA Copper Test Protocol test conditions.

A second aspect of the disclosure pertains to a method of making anantimicrobial composite article, including the steps: providing a matrixcomprising a polymeric material; providing a plurality of second phaseparticles comprising an antimicrobial agent; melting the matrix to forma matrix melt; distributing the plurality of second phase particles inthe matrix melt at a second phase volume fraction to form a compositemelt; forming a composite article from the composite melt; and treatingthe composite article to form an antimicrobial composite article havingan exterior surface comprising an exposed portion of the matrix and theplurality of second phase particles.

The treating step of the method of making the antimicrobial compositearticle in some aspects can include abrading the composite article toform an antimicrobial composite article having an exterior surfacecomprising an exposed portion of the matrix and the plurality of secondphase particles. The abrading can be conducted with hand sanding, gritblasting or other similar grinding and/or polishing techniques. In otheraspects of the method, the treating step can include abrading andplasma-treating the composite article to form an antimicrobial compositearticle having an exterior surface comprising an exposed portion of thematrix and the plurality of second phase particles. In theseimplementations, the abrading can be performed before theplasma-treating or vice versa. Further, the plasma-treating canconducted with any of a variety of known processes that produce orotherwise create functional groups in the exposed portion of the matrixon the exterior surface of the article.

According to some aspects of the method, the melting and distributingsteps can include or otherwise employ an extrusion process. Further, theforming a composite article step can include or otherwise employ aninjection molding process. As such, the forming step can be employed tofashion the composite article in a final product form or a near netshape form.

A third aspect of the disclosure pertains to a method of making anantimicrobial composite article, including the steps: providing a matrixcomprising a hydrophobic polymeric material; providing a plurality ofsecond phase particles comprising a copper-containing antimicrobialagent; melting the matrix to form a matrix melt; extruding the pluralityof second phase particles in the matrix melt at a second phase volumefraction to form a composite melt; injection molding a composite articlefrom the composite melt; and treating the composite article to form anantimicrobial composite article having an exterior surface comprising anexposed portion of the matrix and the plurality of second phaseparticles. Further, the exposed portion of the plurality of second phaseparticles is distributed within the exposed portion of the matrix at asecond phase area fraction within 25% of the second phase volumefraction.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from that description or recognized by practicing theembodiments as described herein, including the detailed descriptionwhich follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework to understanding the natureand character of the claims. The accompanying drawings are included toprovide a further understanding, and are incorporated in and constitutea part of this specification. The drawings illustrate one or moreembodiment(s), and together with the description serve to explainprinciples and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, perspective view of an antimicrobial compositearticle according to an aspect of the disclosure.

FIG. TA is a plan view of an exterior surface of the antimicrobialcomposite article depicted in FIG. 1 that comprises an exposed portionof the matrix and second phase particles.

FIG. 1B is an energy dispersive spectroscopy (EDS) image ofphase-separable glass in an exterior surface of an antimicrobialcomposite article according to an aspect of the disclosure that iscomparable to the antimicrobial composite article schematically depictedin FIG. 1.

FIG. 2 are photographs of antimicrobial composite strip and pelletarticles having a polypropylene matrix and a plurality of second phaseparticles comprising a phase-separable glass with a copper-containingantimicrobial agent according to another aspect of the disclosure.

FIG. 3 are photographs of antimicrobial composite articles having apolypropylene matrix and a plurality of second phase particlescomprising a phase-separable glass with a copper-containingantimicrobial agent that are configured in the form of test coupons forassessing antimicrobial efficacy with the Modified EPA Copper TestProtocol.

FIG. 4 are optical micrographs of an exterior surface of antimicrobialcomposite articles having a polypropylene matrix and a plurality ofsecond phase particles comprising a phase-separable glass with acopper-containing antimicrobial agent before and after a hand-sandingabrasion step according to an aspect of the disclosure.

FIG. 5 are optical micrographs of an exterior surface of theantimicrobial composite articles depicted in FIG. 4, as contacted with abacteria-containing aqueous solution before and after a plasma-treatmentstep according to an aspect of the disclosure.

FIG. 6 is a schematic flow chart of a method of making an antimicrobialcomposite article according to a further aspect of the disclosure.

FIG. 7A is a bar chart depicting the antimicrobial efficacy ofantimicrobial composite articles having a polypropylene matrix and aplurality of second phase particles comprising a phase-separable glasswith a copper-containing antimicrobial agent, and subjected to varioussurface treatment steps.

FIG. 7B is a bar chart depicting the antimicrobial efficacy ofantimicrobial composite articles having a polypropylene matrix and aplurality of second phase particles comprising a phase-separable glasswith a copper-containing antimicrobial agent, and subjected to varioussurface treatment steps.

FIGS. 8A & 8B are bar charts depicting the antimicrobial efficacy ofantimicrobial composite articles having a polysulfone matrix and aplurality of second phase particles comprising a phase-separable glasswith a copper-containing antimicrobial agent, and subjected to varioussurface treatment steps.

FIG. 9 is a bar chart depicting the antimicrobial efficacy ofantimicrobial composite articles having a polypropylene matrix and aplurality of second phase particles comprising a phase-separable glasswith a copper-containing antimicrobial agent, and subjected to varioushospital grade cleaners.

FIGS. 10A & 10B are bar charts depicting the antimicrobial efficacy ofantimicrobial composite articles having a polypropylene matrix and aplurality of second phase particles comprising a phase-separable glasswith a copper-containing antimicrobial agent, and subjected to variousenvironmental conditions.

FIG. 11 is a bar chart depicts the antimicrobial efficacy ofantimicrobial composite articles having a polypropylene matrix and aplurality of second phase particles comprising a phase-separable glasswith a copper-containing antimicrobial agent, with and without asubsequent fluorosilane layer over the exterior surfaces of the article.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiment(s), examplesof which are illustrated in the accompanying drawings.

Aspects of the disclosure generally pertain to antimicrobial compositearticles that include secondary particles comprising glass compositionswith antimicrobial properties. The antimicrobial properties of theglasses disclosed herein include antiviral and/or antibacterialproperties. As used herein the term “antimicrobial,” means a material,or a surface of a material that will kill or inhibit the growth ofbacteria, viruses and/or fungi. The term as used herein does not meanthe material or the surface of the material will kill or inhibit thegrowth of all species microbes within such families, but that it willkill or inhibit the growth or one or more species of microbes from suchfamilies.

As used herein the term “log reduction” means—log (C_(a)/C₀), whereCa=the colony form unit (CFU) number of the antimicrobial surface andC₀=the colony form unit (CFU) of the control surface that is not anantimicrobial surface. As an example, a “3 log” reduction equals about99.9% of the bacteria, viruses and/or fungi killed. Similarly, a “5 log”reduction equals about 99.999% of bacteria, viruses and/or fungi killed.

Referring to FIG. 1, an antimicrobial composite article 100 is providedin an exemplary, schematic form. The article 100 includes a matrix 10that comprises a polymeric material. The article 100 also includes aplurality of second phase particles 20. The particles 20 comprise aphase-separable glass with a copper-containing antimicrobial agent.Further, the plurality of particles 20 is distributed within the matrix10 at a second phase volume fraction. As also depicted in FIG. 1, thecomposite article 100 defines an exterior surface 40 that includes anexposed portion of the matrix 10 and the plurality of the second phaseparticles 20. The exposed portion of the exterior surface 40 is alsodepicted in the plan view of FIG. 1A. In certain implementations, otherexterior surfaces 30 of the article 100 can also include such exposedportions.

Referring again to FIG. 1, the exposed portion of the exterior surface40 can, at least in some aspects, contain a certain percentage of secondphase particles 20 that have been bisected or are otherwise sectionedsuch that their interiors are exposed. In certain implementations, theexposed portion of the plurality of the second phase particles 20 can bedistributed within the exposed portion of the matrix 10 at a secondphase area fraction within ±25% of the second phase volume fraction.That is, the exposed portion of the exterior surface possesses roughlythe same or similar percentage of second phase particles as the bulk ofthe antimicrobial composite article 100.

As outlined earlier, the second phase particles 20 include aphase-separable glass with a copper-containing antimicrobial agent. Thephase-separable glass employed in the particles 20 is described in U.S.patent application Ser. No. 14/623,077, filed on Feb. 16, 2015, thesalient portions of which related to phase-separable glass are herebyincorporated by reference within this disclosure. In one or moreembodiments, the phase-separable glasses employed in the second phaseparticles 20 include a Cu species. In one or more alternativeembodiments, the Cu species may include Cu¹⁺, Cu⁰, and/or Cu²⁺. Thecombined total of the Cu species may be about 10 wt % or more. However,as will be discussed in more detail below, the amount of Cu²⁺ isminimized or is reduced such that the antimicrobial glass issubstantially free of Cu²⁺. The Cu¹⁺ ions may be present on or in thesurface and/or the bulk of the antimicrobial glass. In some embodiments,the Cu¹⁺ ions are present in the glass network and/or the glass matrixof the antimicrobial glass. Where the Cu¹⁺ ions are present in the glassnetwork, the Cu¹⁺ ions are atomically bonded to the atoms in the glassnetwork. Where the Cu¹⁺ ions are present in the glass matrix, the Cu¹⁺ions may be present in the form of Cu¹⁺ crystals that are dispersed inthe glass matrix. In some embodiments the Cu¹⁺ crystals include cuprite(Cu₂O). In such embodiments, where Cu¹⁺ crystals are present, thematerial may be referred to as an antimicrobial glass ceramic, which isintended to refer to a specific type of glass with crystals that may ormay not be subjected to a traditional ceramming process by which one ormore crystalline phases are introduced and/or generated in the glass.Where the Cu¹⁺ ions are present in a non-crystalline form, the materialmay be referred to as an antimicrobial glass. In some embodiments, bothCu¹⁺ crystals and Cu¹⁺ ions not associated with a crystal are present inthe antimicrobial glasses described herein.

In one or more aspects of the antimicrobial composite article 100, theantimicrobial glass employed in the second phase particles 20 may beformed from a composition that can include, in mole percent, SiO₂ in therange from about 40 to about 70, Al₂O₃ in the range from about 0 toabout 20, a copper-containing oxide in the range from about 10 to about30, CaO in the range from about 0 to about 15, MgO in the range fromabout 0 to about 15, P₂O₅ in the range from about 0 to about 25, B₂O₃ inthe range from about 0 to about 25, K₂O in the range from about 0 toabout 20, ZnO in the range from about 0 to about 5, Na₂O in the rangefrom about 0 to about 20, and/or Fe₂O₃ in the range from about 0 toabout 5. In such embodiments, the amount of the copper-containing oxideis greater than the amount of Al₂O₃. In some embodiments, thecomposition may include a content of R₂O, where R may include K, Na, Li,Rb, Cs and combinations thereof.

In the embodiments of the compositions described herein, SiO₂ serves asthe primary glass-forming oxide. The amount of SiO₂ present in acomposition should be enough to provide glasses that exhibit therequisite chemical durability suitable for its use or application withinthe antimicrobial composite article 100 (e.g., touch applications,article housing etc.). The upper limit of SiO₂ may be selected tocontrol the melting temperature of the compositions described herein.For example, excess SiO₂ could drive the melting temperature at 200poise to high temperatures at which defects such as fining bubbles mayappear or be generated during processing and in the resulting glass.Furthermore, compared to most oxides, SiO₂ decreases the compressivestress created by an ion exchange process of the resulting glass. Inother words, glass formed from compositions with excess SiO₂ may not beion-exchangeable to the same degree as glass formed from compositionswithout excess SiO₂. Additionally or alternatively, SiO₂ present in thecompositions according to one or more embodiments could increase theplastic deformation prior break properties of the resulting glass. Anincreased SiO₂ content in the glass formed from the compositionsdescribed herein may also increase the indentation fracture threshold ofthe glass.

In one or more aspects of the antimicrobial composite article 100, thecomposition of the glass employed in the second phase particles 20includes SiO₂ in an amount, in mole percent, in the range from about 40to about 70, from about 40 to about 69, from about 40 to about 68, fromabout 40 to about 67, from about 40 to about 66, from about 40 to about65, from about 40 to about 64, from about 40 to about 63, from about 40to about 62, from about 40 to about 61, from about 40 to about 60, fromabout 41 to about 70, from about 42 to about 70, from about 43 to about70, from about 44 to about 70, from about 45 to about 70, from about 46to about 70, from about 47 to about 70, from about 48 to about 70, fromabout 49 to about 70, from about 50 to about 70, from about 41 to about69, from about 42 to about 68, from about 43 to about 67 from about 44to about 66 from about 45 to about 65, from about 46 to about 64, fromabout 47 to about 63, from about 48 to about 62, from about 49 to about61, from about 50 to about 60 and all ranges and sub-rangestherebetween.

In one or more aspects of the antimicrobial composite article 100, thecomposition of the glass employed in the second phase particles 20includes Al₂O₃ an amount, in mole percent, in the range from about 0 toabout 20, from about 0 to about 19, from about 0 to about 18, from about0 to about 17, from about 0 to about 16, from about 0 to about 15, fromabout 0 to about 14, from about 0 to about 13, from about 0 to about 12,from about 0 to about 11 from about 0 to about 10, from about 0 to about9, from about 0 to about 8, from about 0 to about 7, from about 0 toabout 6, from about 0 to about 5, from about 0 to about 4, from about 0to about 3, from about 0 to about 2, from about 0 to about 1, from about0.1 to about 1, from about 0.2 to about 1, from about 0.3 to about 1from about 0.4 to about 1 from about 0.5 to about 1, from about 0 toabout 0.5, from about 0 to about 0.4, from about 0 to about 0.3 fromabout 0 to about 0.2, from about 0 to about 0.1 and all ranges andsub-ranges therebetween. In some embodiments, the composition issubstantially free of Al₂O₃. As used herein, the phrase “substantiallyfree” with respect to the components of the composition and/or resultingglass means that the component is not actively or intentionally added tothe compositions during initial batching or subsequent post processing(e.g., ion exchange process), but may be present as an impurity. Forexample, a composition, a glass may be describe as being substantiallyfree of a component, when the component is present in an amount of lessthan about 0.01 mol %.

The amount of Al₂O₃ may be adjusted to serve as a glass-forming oxideand/or to control the viscosity of molten compositions within the glassemployed in the second phase particles 20. Without being bound bytheory, it is believed that when the concentration of alkali oxide (R₂O)in a composition is equal to or greater than the concentration of Al₂O₃,the aluminum ions are found in tetrahedral coordination with the alkaliions acting as charge-balancers. This tetrahedral coordination greatlyenhances various post-processing (e.g., ion exchange process) of glassesformed from such compositions. Divalent cation oxides (RO) can alsocharge balance tetrahedral aluminum to various extents. While elementssuch as calcium, zinc, strontium, and barium behave equivalently to twoalkali ions, the high field strength of magnesium ions causes them tonot fully charge balance aluminum in tetrahedral coordination, resultingin the formation of five- and six-fold coordinated aluminum. Generally,Al₂O₃ can play an important role in ion-exchangeable compositions andstrengthened glasses since it enables a strong network backbone (i.e.,high strain point) while allowing for the relatively fast diffusivity ofalkali ions. However, when the concentration of Al₂O₃ is too high, thecomposition may exhibit lower liquidus viscosity and, thus, Al₂O₃concentration may be controlled within a reasonable range. Moreover, aswill be discussed in more detail below, excess Al₂O₃ has been found topromote the formation of Cu² ions, instead of the desired Cu¹⁺ ions.

In one or more aspects of the antimicrobial composite article 100, thecomposition of the glass employed in the second phase particles 20includes a copper-containing oxide in an amount, in mole percent, in therange from about 10 to about 50, from about 10 to about 49, from about10 to about 48, from about 10 to about 47, from about 10 to about 46,from about 10 to about 45, from about 10 to about 44, from about 10 toabout 43, from about 10 to about 42, from about 10 to about 41, fromabout 10 to about 40, from about 10 to about 39, from about 10 to about38, from about 10 to about 37, from about 10 to about 36, from about 10to about 35, from about 10 to about 34, from about 10 to about 33, fromabout 10 to about 32, from about 10 to about 31, from about 10 to about30, from about 10 to about 29, from about 10 to about 28, from about 10to about 27, from about 10 to about 26, from about 10 to about 25, fromabout 10 to about 24, from about 10 to about 23, from about 10 to about22, from about 10 to about 21, from about 10 to about 20, from about 11to about 50, from about 12 to about 50, from about 13 to about 50, fromabout 14 to about 50, from about 15 to about 50, from about 16 to about50, from about 17 to about 50, from about 18 to about 50, from about 19to about 50, from about 20 to about 50, from about 10 to about 30, fromabout 11 to about 29, from about 12 to about 28, from about 13 to about27, from about 14 to about 26, from about 15 to about 25, from about 16to about 24, from about 17 to about 23, from about 18 to about 22, fromabout 19 to about 21 and all ranges and sub-ranges therebetween. In oneor more specific embodiments, the copper-containing oxide may be presentin the composition in an amount of about 20 mole percent, about 25 molepercent, about 30 mole percent or about 35 mole percent. Thecopper-containing oxide may include CuO, Cu₂O and/or combinationsthereof.

The copper-containing oxides in the composition form the Cu¹⁺ ionspresent in the resulting glass. Copper may be present in the compositionand/or the glasses including the composition in various forms includingCu⁰, Cu¹⁺, and Cu²⁺. Copper in the Cu or Cu¹⁺ forms provideantimicrobial activity. However forming and maintaining these states ofantimicrobial copper are difficult and often, in known compositions,Cu²⁺ ions are formed instead of the desired Cu⁰ or Cu¹⁺ ions.

In one or more aspects of the antimicrobial composite article 100, theamount of copper-containing oxide in the glass of the second phaseparticles 20 is greater than the amount of Al₂O₃ in the composition.Without being bound by theory it is believed that an about equal amountof copper-containing oxides and Al₂O₃ in the composition results in theformation of tenorite (CuO) instead of cuprite (Cu₂O). The presence oftenorite decreases the amount of Cu¹⁺ in favor of Cu²⁺ and thus leads toreduced antimicrobial activity. Moreover, when the amount ofcopper-containing oxides is about equal to the amount of Al₂O₃, aluminumprefers to be in a four-fold coordination and the copper in thecomposition and resulting glass remains in the Cu²⁺ form so that thecharge remains balanced. Where the amount of copper-containing oxideexceeds the amount of Al₂O₃, then it is believed that at least a portionof the copper is free to remain in the Cu¹⁺ state, instead of the Cu²⁺state, and thus the presence of Cu¹⁺ ions increases.

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 includes P₂O₅ in an amount, in mole percent, in the rangefrom about 0 to about 25, from about 0 to about 22, from about 0 toabout 20, from about 0 to about 18, from about 0 to about 16, from about0 to about 15, from about 0 to about 14, from about 0 to about 13, fromabout 0 to about 12, from about 0 to about 11, from about 0 to about 10,from about 0 to about 9, from about 0 to about 8, from about 0 to about7, from about 0 to about 6, from about 0 to about 5, from about 0 toabout 4, from about 0 to about 3, from about 0 to about 2, from about 0to about 1, from about 0.1 to about 1, from about 0.2 to about 1, fromabout 0.3 to about 1 from about 0.4 to about 1 from about 0.5 to about1, from about 0 to about 0.5, from about 0 to about 0.4, from about 0 toabout 0.3 from about 0 to about 0.2, from about 0 to about 0.1 and allranges and sub-ranges therebetween. In some embodiments, the compositionincludes about 10 mole percent or about 5 mole percent P₂O₅ or,alternatively, may be substantially free of P₂O₅.

In one or more embodiments, P₂O₅ forms at least part of a less durablephase or a degradable phase in the glass employed in the second phaseparticles 20 of the antimicrobial composite article 100. Therelationship between the degradable phase(s) of the glass andantimicrobial activity is discussed in greater detail herein. In one ormore embodiments, the amount of P₂O₅ may be adjusted to controlcrystallization of the composition and/or glass during forming. Forexample, when the amount of P₂O₅ is limited to about 5 mol % or less oreven 10 mol % or less, crystallization may be minimized or controlled tobe uniform. However, in some embodiments, the amount or uniformity ofcrystallization of the composition and/or glass may not be of concernand thus, the amount of P₂O₅ utilized in the composition may be greaterthan 10 mol %.

In one or more embodiments, the amount of P₂O₅ in the composition may beadjusted based on the desired damage resistance of the glass employed inthe second phase particles 20 of the antimicrobial composite article100, despite the tendency for P₂O₅ to form a less durable phase or adegradable phase in the glass. Without being bound by theory, P₂O₅ candecrease the melting viscosity relative to SiO₂. In some instances, P₂O₅is believed to help to suppress zircon breakdown viscosity (i.e., theviscosity at which zircon breaks down to form ZrO₂) and may be moreeffective in this regard than SiO₂. When glass is to be chemicallystrengthened via an ion exchange process, P₂O₅ can improve thediffusivity and decrease ion exchange times, when compared to othercomponents that are sometimes characterized as network formers (e.g.,SiO₂ and/or B₂O₃).

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 includes B₂O₃ in an amount, in mole percent, in the rangefrom about 0 to about 25, from about 0 to about 22, from about 0 toabout 20, from about 0 to about 18, from about 0 to about 16, from about0 to about 15, from about 0 to about 14, from about 0 to about 13, fromabout 0 to about 12, from about 0 to about 11, from about 0 to about 10,from about 0 to about 9, from about 0 to about 8, from about 0 to about7, from about 0 to about 6, from about 0 to about 5, from about 0 toabout 4, from about 0 to about 3, from about 0 to about 2, from about 0to about 1, from about 0.1 to about 1, from about 0.2 to about 1, fromabout 0.3 to about 1 from about 0.4 to about 1 from about 0.5 to about1, from about 0 to about 0.5, from about 0 to about 0.4, from about 0 toabout 0.3 from about 0 to about 0.2, from about 0 to about 0.1 and allranges and sub-ranges therebetween. In some embodiments, the compositionincludes a non-zero amount of B₂O₃, which may be, for example, about 10mole percent or about 5 mole percent. The composition of someembodiments may be substantially free of B₂O₃.

In one or more embodiments, B₂O₃ forms a less durable phase or adegradable phase in the glass employed in the second phase particles 20of the antimicrobial composite article 100. The relationship between thedegradable phase(s) of the glass and antimicrobial activity is discussedin greater detail herein. Without being bound by theory, it is believedthe inclusion of B₂O₃ in compositions imparts damage resistance inglasses incorporating such compositions, despite the tendency for B₂O₃to form a less durable phase or a degradable phase in the glass. Thecomposition of one or more embodiments includes one or more alkalioxides (R₂O) (e.g., Li₂O, Na₂O, K₂O, Rb₂O and/or Cs₂O). In someembodiments, the alkali oxides modify the melting temperature and/orliquidus temperatures of such compositions. In one or more embodiments,the amount of alkali oxides may be adjusted to provide a compositionexhibiting a low melting temperature and/or a low liquidus temperature.Without being bound by theory, the addition of alkali oxide(s) mayincrease the coefficient of thermal expansion (CTE) and/or lower thechemical durability of the antimicrobial glasses that include suchcompositions. In some cases these attributes may be altered dramaticallyby the addition of alkali oxide(s).

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 may include one or more divalent cation oxides, such asalkaline earth oxides and/or ZnO. Such divalent cation oxides may beincluded to improve the melting behavior of the compositions.

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 may include CaO in an amount, in mole percent, in the rangefrom about 0 to about 15, from about 0 to about 14, from about 0 toabout 13, from about 0 to about 12, from about 0 to about 11, from about0 to about 10, from about 0 to about 9, from about 0 to about 8, fromabout 0 to about 7, from about 0 to about 6, from about 0 to about 5,from about 0 to about 4, from about 0 to about 3, from about 0 to about2, from about 0 to about 1, from about 0.1 to about 1, from about 0.2 toabout 1, from about 0.3 to about 1 from about 0.4 to about 1 from about0.5 to about 1, from about 0 to about 0.5, from about 0 to about 0.4,from about 0 to about 0.3 from about 0 to about 0.2, from about 0 toabout 0.1 and all ranges and sub-ranges therebetween. In someembodiments, the composition is substantially free of CaO.

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 may include MgO in an amount, in mole percent, in the rangefrom about 0 to about 15, from about 0 to about 14, from about 0 toabout 13, from about 0 to about 12, from about 0 to about 11, from about0 to about 10, from about 0 to about 9, from about 0 to about 8, fromabout 0 to about 7, from about 0 to about 6, from about 0 to about 5,from about 0 to about 4, from about 0 to about 3, from about 0 to about2, from about 0 to about 1, from about 0.1 to about 1, from about 0.2 toabout 1, from about 0.3 to about 1 from about 0.4 to about 1 from about0.5 to about 1, from about 0 to about 0.5, from about 0 to about 0.4,from about 0 to about 0.3 from about 0 to about 0.2, from about 0 toabout 0.1 and all ranges and sub-ranges therebetween. In someembodiments, the composition is substantially free of MgO.

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 may include ZnO in an amount, in mole percent, in the rangefrom about 0 to about 5, from about 0 to about 4, from about 0 to about3, from about 0 to about 2, from about 0 to about 1, from about 0.1 toabout 1, from about 0.2 to about 1, from about 0.3 to about 1 from about0.4 to about 1 from about 0.5 to about 1, from about 0 to about 0.5,from about 0 to about 0.4, from about 0 to about 0.3 from about 0 toabout 0.2, from about 0 to about 0.1 and all ranges and sub-rangestherebetween. In some embodiments, the composition is substantially freeof ZnO.

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 may include Fe₂O₃, in mole percent, in the range from about0 to about 5, from about 0 to about 4, from about 0 to about 3, fromabout 0 to about 2, from about 0 to about 1, from about 0.1 to about 1,from about 0.2 to about 1, from about 0.3 to about 1 from about 0.4 toabout 1 from about 0.5 to about 1, from about 0 to about 0.5, from about0 to about 0.4, from about 0 to about 0.3 from about 0 to about 0.2,from about 0 to about 0.1 and all ranges and sub-ranges therebetween. Insome embodiments, the composition is substantially free of Fe₂O₃.

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 may include one or more colorants. Examples of suchcolorants include NiO, TiO₂, Fe₂O₃, Cr₂O₃, Co₃O₄ and other knowncolorants. In some embodiments, the one or more colorants may be presentin an amount in the range up to about 10 mol %. In some instances, theone or more colorants may be present in an amount in the range fromabout 0.01 mol % to about 10 mol %, from about 1 mol % to about 10 mol%, from about 2 mol % to about 10 mol %, from about 5 mol % to about 10mol %, from about 0.01 mol % to about 8 mol %, or from about 0.01 mol %to about 5 mol %. In some aspects, the colorant employed in the secondphase particles 20 is selected to match the color of the matrix employedin the antimicrobial composite article 100.

In one or more aspects of the antimicrobial composite article 100, thecomposition of one or more embodiments of the glass of the second phaseparticles 20 may include one or more nucleating agents. Exemplarynucleating agents include TiO₂, ZrO₂ and other known nucleating agentsin the art. The composition can include one or more different nucleatingagents. The nucleating agent content of the composition may be in therange from about 0.01 mol % to about 1 mol %. In some instances, thenucleating agent content may be in the range from about 0.01 mol % toabout 0.9 mol %, from about 0.01 mol % to about 0.8 mol %, from about0.01 mol % to about 0.7 mol %, from about 0.01 mol % to about 0.6 mol %,from about 0.01 mol % to about 0.5 mol %, from about 0.05 mol % to about1 mol %, from about 0.1 mol % to about 1 mol %, from about 0.2 mol % toabout 1 mol %, from about 0.3 mol % to about 1 mol %, or from about 0.4mol % to about 1 mol %, and all ranges and sub-ranges therebetween.

The glasses formed from the compositions, as employed in the secondphase particles 20 of the antimicrobial composite article 100, mayinclude a plurality of Cu¹⁺ ions. In some embodiments, such Cu¹⁺ ionsform part of the glass network and may be characterized as a glassmodifier. Without being bound by theory, where Cu¹⁺ ions are part of theglass network, it is believed that during typical glass formationprocesses, the cooling step of the molten glass occurs too rapidly toallow crystallization of the copper-containing oxide (e.g., CuO and/orCu₂O). Thus the Cu¹⁺ remains in an amorphous state and becomes part ofthe glass network. In some cases, the total amount of Cu¹⁺ ions, whetherthey are in a crystalline phase or in the glass matrix, may be evenhigher, such as up to 40 mol %, up to 50 mol %, or up to 60 mol %.

In one or more embodiments, the glasses formed form the compositionsdisclosed herein, as employed in the second phase particles 20 of theantimicrobial composite article 100, include Cu¹⁺ ions that aredispersed in the glass matrix as Cu¹⁺ crystals. In one or moreembodiments, the Cu¹⁺ crystals may be present in the form of cuprite.The cuprite present in the glass may form a phase that is distinct fromthe glass matrix or glass phase. In other embodiments, the cuprite mayform part of or may be associated with one or more glasses phases (e.g.,the durable phase described herein). The Cu¹⁺ crystals may have anaverage major dimension of about 5 micrometers (μm) or less, 4micrometers (μm) or less, 3 micrometers (μm) or less, 2 micrometers (μm)or less, about 1.9 micrometers (μm) or less, about 1.8 micrometers (μm)or less, about 1.7 micrometers (μm) or less, about 1.6 micrometers (μm)or less, about 1.5 micrometers (μm) or less, about 1.4 micrometers (μm)or less, about 1.3 micrometers (μm) or less, about 1.2 micrometers (μm)or less, about 1.1 micrometers or less, 1 micrometers or less, about 0.9micrometers (μm) or less, about 0.8 micrometers (μm) or less, about 0.7micrometers (μm) or less, about 0.6 micrometers (μm) or less, about 0.5micrometers (μm) or less, about 0.4 micrometers (μm) or less, about 0.3micrometers (μm) or less, about 0.2 micrometers (μm) or less, about 0.1micrometers (μm) or less, about 0.05 micrometers (μm) or less, and allranges and sub-ranges therebetween. As used herein and with respect tothe phrase “average major dimension”, the word “average” refers to amean value and the word “major dimension” is the greatest dimension ofthe particle as measured by scanning electron microscopy (SEM). In someembodiments, the cuprite phase may be present in the glass of the secondphase particles 20 of the antimicrobial composite article 100 in anamount of at least about 10 wt %, at least about 15 wt %, at least about20 wt %, at least about 25 wt % and all ranges and subrangestherebetween of the antimicrobial glass. In certain implementations, thephase-separable glasses formed from the compositions disclosed herein,as employed in the second phase particles 20 of the antimicrobialcomposite article 100, can include 10 to 50 mol % cuprite, and allranges and subranges therebetween, of the phase-separable glass.

In some embodiments, the glasses as employed in the second phaseparticles 20 of the antimicrobial composite article 100 may includeabout 70 wt % Cu¹⁺ or more and about 30 wt % of Cu²⁺ or less. The Cu²⁺ions may be present in tenorite form and/or even in the glass (i.e., notas a crystalline phase).

In some embodiments, the total amount of Cu by wt % in the glasses asemployed in the second phase particles 20 of the antimicrobial compositearticle 100 may be in the range from about 10 to about 30, from about 15to about 25, from about 11 to about 30, from about 12 to about 30, fromabout 13 to about 30, from about 14 to about 30, from about 15 to about30, from about 16 to about 30, from about 17 to about 30, from about 18to about 30, from about 19 to about 30, from about 20 to about 30, fromabout 10 to about 29, from about 10 to about 28, from about 10 to about27, from about 10 to about 26, from about 10 to about 25, from about 10to about 24, from about 10 to about 23, from about 10 to about 22, fromabout 10 to about 21, from about 10 to about 20, from about 16 to about24, from about 17 to about 23, from about 18 to about 22, from about 19to about 21 and all ranges and sub-ranges therebetween. In one or moreembodiments, the ratio of Cu¹⁺ ions to the total amount Cu in the glassis about 0.5 or greater, 0.55 or greater, 0.6 or greater, 0.65 orgreater, 0.7 or greater, 0.75 or greater, 0.8 or greater, 0.85 orgreater, 0.9 or greater or even 1 or greater, and all ranges andsub-ranges therebetween. The amount of Cu and the ratio of Cu¹⁺ ions tototal Cu may be determined by inductively coupled plasma (ICP)techniques known in the art.

In some embodiments, the glass as employed in the second phase particles20 of the antimicrobial composite article 100 may exhibit a greateramount of Cu¹⁺ and/or Cu0 than Cu²⁺. For example, based on the totalamount of Cu¹⁺, Cu²⁺ and Cu0 in the glasses, the percentage of Cu¹⁺ andCu⁰, combined, may be in the range from about 50% to about 99.9%, fromabout 50% to about 99%, from about 50% to about 95%, from about 50% toabout 90%, from about 55% to about 99.9%, from about 60% to about 99.9%,from about 65% to about 99.9%, from about 70% to about 99.9%, from about75% to about 99.9%, from about 80% to about 99.9%, from about 85% toabout 99.9%, from about 90% to about 99.9%, from about 95% to about99.9%, and all ranges and sub-ranges therebetween. The relative amountsof Cu¹⁺, Cu²⁺ and Cu⁰ may be determined using x-ray photoluminescencespectroscopy (XPS) techniques known in the art.

Referring again to FIGS. 1 and 1A, the plurality of second phaseparticles 20 of the antimicrobial composite article 100 can employ aphase-separable glass. In particular, the phase-separable glass cancomprise at least a first phase and a second phase (distinct from thesecond phase particles 20). In one or more embodiments, thephase-separable glass may include two or more phases wherein the phasesdiffer based on the ability of the atomic bonds in the given phase towithstand interaction with a leachate. Specifically, the glass of one ormore embodiments may include a first phase that may be described as adegradable phase and a second phase that may be described as a durablephase. The phrases “first phase” and “degradable phase” may be usedinterchangeably. The phrases “second phase” and “durable phase” may beused interchangeably in the context of the phase-separable glass. Asused herein, the term “durable” refers to the tendency of the atomicbonds of the durable phase to remain intact during and after interactionwith a leachate. As used herein, the term “degradable” refers to thetendency of the atomic bonds of the degradable phase to break during andafter interaction with one or more leachates. In one or moreembodiments, the durable phase includes SiO₂ and the degradable phaseincludes at least one of B₂O₃, P₂O₅ and R₂O (where R can include any oneor more of K, Na, Li, Rb, and Cs). Without being bound by theory, it isbelieved that the components of the degradable phase (i.e., B₂O₃, P₂O₅and/or R₂O) more readily interact with a leachate and the bonds betweenthese components to one another and to other components in thephase-separable glass more readily break during and after theinteraction with the leachate. Leachates may include water, acids orother similar materials. In one or more embodiments, the degradablephase withstands degradation for 1 week or longer, 1 month or longer, 3months or longer, or even 6 months or longer. In some embodiments,longevity may be characterized as maintaining antimicrobial efficacyover a specific period of time.

In one or more embodiments of the antimicrobial composite article 100,the durable phase of the phase-separable glass employed in the secondphase particles is present in an amount by weight that is greater thanthe amount of the degradable phase. In some instances, the degradablephase forms islands and the durable phase forms the sea surrounding theislands (i.e., the durable phase). In one or more embodiments, eitherone or both of the durable phase and the degradable phase may includecuprite. The cuprite in such embodiments may be dispersed in therespective phase or in both phases.

In some embodiments of the phase-separable glass, phase separationoccurs without any additional heat treatment of the glass. In someembodiments, phase separation may occur during melting and may bepresent when the glass composition is melted at temperatures up to andincluding about 1600° C. or 1650° C. When the glass is cooled, the phaseseparation is maintained (e.g., in a metastable state).

The phase-separable glass, as described in the foregoing, may beprovided as a sheet or may have another shape such as particulate,fibrous, and the like. Referring to FIGS. 1 and 1A, the phase-separableglass is in the form of second phase particles 20, generally bounded bya matrix 10 that comprises a polymeric material. In the second phaseparticles 20 within the exposed portion of exterior surface 40, thesurface portion of the particles 20 may include a plurality of copperions wherein at least 75% of the plurality of copper ions includesCu¹⁺-ions. For example, in some instances, at least about 80%, at leastabout 85%, at least about 90%, at least about 95%, at least about 98%,at least about 99% or at least about 99.9% of the plurality of copperions in the surface portion includes Cu¹⁺ ions. In some embodiments, 25%or less (e.g., 20% or less, 15% or less, 12% or less, 10% or less or 8%or less) of the plurality of copper ions in the surface portion includeCu²⁺ ions. For example, in some instances, 20% or less, 15% or less, 10%or less, 5% or less, 2% or less, 1% or less, 0.5% or less or 0.01% orless of the plurality of copper ions in the surface portion include Cu²⁺ions. In some embodiments, the surface concentration of Cu¹⁺ ions in theantimicrobial glass is controlled. In some instances, a Cu¹⁺ ionconcentration of about 4 ppm or greater can be provided on the surfaceof the antimicrobial glass.

The antimicrobial composite articles 100 according to one or moreembodiments, and particularly their exterior surfaces 30 and 40 withexposed portions, may exhibit a 2 log reduction or greater (e.g., 2.5,3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 and all ranges and sub-rangestherebetween) in a concentration of at least one of Staphylococcusaureus, Enterobacter aerogenes, Pseudomonas aeruginosa,methicillin-resistant Staphylococcus aureus (MRSA), and E. coli bacteriaunder modified United States Environmental Protection Agency “TestMethod for Efficacy of Copper Alloy Surfaces as a Sanitizer” (2009)testing conditions, wherein the modified conditions include substitutionof the antimicrobial composite article with the copper-containingsurface prescribed in the Method and use of copper metal article as theprescribed control sample in the Method (collectively, the “Modified EPACopper Test Protocol”). As such, the United States EnvironmentalProtection Agency “Test Method for Efficacy of Copper Alloy Surfaces asa Sanitizer” (2009) is hereby incorporated by reference in its entiretywithin the disclosure. In some instances, the antimicrobial compositearticles exhibit at least a 4 log reduction, a 5 log reduction or even a6 log reduction in the concentration of at least one of Staphylococcusaureus, Enterobacter aerogenes, Pseudomonas aeruginosa bacteria, MRSA,and E. coli under the Modified EPA Copper Test Protocol.

The antimicrobial composite articles 100 according to one or moreembodiments may exhibit the log reductions described herein for longperiods of time. In other words, the articles 100 may exhibit extendedor prolonged antimicrobial efficacy. For example, in some embodiments,the antimicrobial composite articles 100 may exhibit the log reductionsdescribed herein under the Modified EPA Copper Test Protocol for a week,two weeks, three weeks, up to 1 month, up to 3 months, up to 6 months orup to 12 months after the antimicrobial composite article 100 is formedor after the phase-separable glass is combined with a carrier (e.g.,polymeric matrix 10). These time periods may start at or after theantimicrobial composite article 100 is formed or combined with a carrierincluding but not limited to matrix 10.

According to one or more embodiments, the phase-separable glass of thesecond phase particle 20 may exhibit a preservative function, whencombined with the matrix 10 described herein. In such embodiments, thephase-separable glass may kill or eliminate, or reduce the growth ofvarious foulants in the matrix 10. Foulants include fungi, bacteria,viruses and combinations thereof.

According to one or more embodiments, the antimicrobial compositearticles 100 containing the phase-separable glasses described hereinleach copper ions when exposed or in contact with a leachate. In one ormore embodiments, the glass leaches only copper ions when exposed toleachates including water.

In one or more embodiments, the antimicrobial composite articles 100described herein may have a tunable antimicrobial activity release. Theantimicrobial activity of the phase-separable glass may be caused bycontact between the second phase particles 20 containing the glass and aleachate, such as water, where the leachate causes Cu¹⁺ ions to bereleased from the glass. This action may be described as watersolubility and the water solubility can be tuned to control the releaseof the Cu⁺¹ ions.

In some embodiments, where the Cu¹⁺ ions are disposed in the glassnetwork and/or form atomic bonds with the atoms in the glass network ofthe phase-separable glass, water or humidity breaks those bonds and theCu¹⁺ ions available for release and may be exposed on the second phaseparticles 20.

In one or more embodiments of the antimicrobial composite articles 100,the phase-separable glass may be formed using formed in low cost meltingtanks that are typically used for melting glass compositions such assoda lime silicate. Such phase-separable glass may be formed into asheet or directly into a particulate using forming processes known inthe art. For instance, example forming methods include float glassprocesses and down-draw processes such as fusion draw and slot draw.When the phase-separable glass is formed into a sheet, it issubsequently ground or otherwise processed to form the second phaseparticles 20 employed in the antimicrobial composite article 100.

In some implementations, the phase-separable glass may be incorporatedinto a variety of antimicrobial composite articles (e.g., article 100)and forms, either alone or in combination with other materials, such aselectronic devices (e.g., mobile phones, smart phones, tablets, videoplayers, information terminal devices, laptop computer, etc.),architectural structures (e.g., countertops or walls), appliances (e.g.,cooktops, refrigerator and dishwasher doors, etc.), information displays(e.g., whiteboards), automotive components (e.g., dashboard panels,windshields, window components, etc.), counter-tops, table-tops, doorknobs, rails, elevator control panels and other article having “hightouch” surfaces. When used in such antimicrobial composite articles, thephase-separable glass can form at least part of the housing and/ordisplay, e.g., by virtue of its concentration within the article assecond phase particles 20 in the matrix 10.

After formation, the phase-separable glass may be formed into sheets andmay be shaped, polished or otherwise processed for a desired end use. Insome instances, the phase-separable glass is ground to a powder orparticulate form to serve as the second phase particles 20 employed inthe matrix 10 of the antimicrobial composite article. The combination ofthe phase-separable glass and the matrix material (e.g., a polymericmaterial serving as matrix 10) may be suitable for injection molding,extrusion or coatings. Such other materials or matrix materials mayinclude polymers, monomers, binders, solvents, or a combination thereofas described herein. The polymer used in the embodiments describedherein can include a thermoplastic polymer (e.g., a polyolefin), a curedpolymer (e.g., an ultraviolet- or UV-cured polymer, thermosettingpolymer, thermosetting coating, etc.), a polymer emulsion, asolvent-based polymer, and combinations thereof. Examples of suitablepolymers include, without limitation: thermoplastics includingpolysulfone (PU), polystyrene (PS), high impact PS, polycarbonate (PC),nylon (sometimes referred to as polyamide (PA)),poly(acrylonitrile-butadiene-styrene) (ABS), PC-ABS blends,polybutyleneterephthlate (PBT) and PBT co-polymers,polyethyleneterephthalate (PET) and PET co-polymers, polyolefins (PO)including polyethylenes (PE), polypropylenes (PP), cyclicpolyolefins(cyclic-PO), modified polyphenylene oxide (mPPO), polyvinylchloride(PVC), acrylic polymers including polymethyl methacrylate (PMMA),thermoplastic elastomers (TPE), thermoplastic urethanes (TPU),polyetherimide (PEl) and blends of these polymers with each other.Suitable injection moldable thermosetting polymers include epoxy,acrylic, styrenic, phenolic, melamine, urethanes, polyesters andsilicone resins. In certain aspects, the matrix material serving asmatrix 10 can comprise a low (e.g., a polyolefin) or a high (e.g.,polyethyleneimine) melting point polymeric material. According to someaspects, the matrix comprises a low or high molecular weight polymericmaterial. It should also be understood that the matrix material cancomprise a bulk polymeric material (e.g., pure polyolefin), a blend ofpolymeric materials (e.g., a polyethylene/polypropylene mixture) and/ora composite polymeric material (e.g., a polyolefin/glass composite).Other suitable polymeric variants include linear, ladder and branchedpolymers (e.g., star polymers, brush polymers and dendrons/dentrimers).Another polymeric material variant that can be employed for the matrix10 includes copolymers (e.g., linear, branched and cyclo/ring).

In other embodiments, the polymers may be dissolved in a solvent ordispersed as a separate phase in a solvent and form a polymer emulsion,such as a latex (which is a water emulsion of a synthetic or naturalrubber, or plastic obtained by polymerization and used especially incoatings (as paint) and adhesives. Polymers may include fluorinatedsilanes or other low friction or anti-frictive materials. The polymerscan contain impact modifiers, flame retardants, UV inhibitors,antistatic agents, mold release agents, fillers including glass, metalor carbon fibers or particles (including spheres), talc, clay or micaand colorants. Specific examples of monomers include catalyst curablemonomers, thermally-curable monomers, radiation-curable monomers andcombinations thereof.

In one or more embodiments, the phase-separable glass may be provided inparticulate form as second phase particles 20. In this form, thephase-separable glass may have a diameter in the range from about 0.1micrometers (μm) (μm) to about 10 micrometers (μm) (μm), from about 0.1micrometers (μm) (μm) to about 9 micrometers (μm) (μm), from about 0.1micrometers (μm) (μm) to about 8 micrometers (μm) (μm), from about 0.1micrometers (μm) (μm) to about 7 micrometers (μm) (μm), from about 0.1micrometers (μm) (μm) to about 6 micrometers (μm) (μm), from about 0.5micrometers (μm) (μm) to about 10 micrometers (μm) (μm), from about 0.75micrometers (μm) (μm) to about 10 micrometers (μm) (μm), from about 1micrometers (μm) (μm) to about 10 micrometers (μm) (μm), from about 2micrometers (μm) (μm) to about 10 micrometers (μm) (μm), from about 3micrometers (μm) (μm) to about 10 micrometers (μm) (μm) from about 3micrometers (μm) (μm) to about 6 micrometers (μm) (μm), from about 3.5micrometers (μm) (μm) to about 5.5 micrometers (μm) (μm), from about 4micrometers (μm) (μm), to about 5 micrometers (μm) (μm), and all rangesand sub-ranges therebetween. The glass may be substantially spherical ormay have an irregular shape.

Without being bound by theory it is believed that the combination of thephase-separable glass described herein (e.g., within second phaseparticles 20) and a matrix (e.g., matrix 1), such as a polypropylene orpolysulfone material, provides substantially greater antimicrobialefficacy as compared to the same matrix materials that includes onlyCu₂O (cuprite), even when the same amount of copper is utilized. Thepresence of Cu¹⁺ crystals in the phase-separable glasses describedherein, even when present as cuprite, tends to remain in the Cu¹⁺ state.Without being bound by theory, it is believed that when Cu₂O is providedalone, separate from the phase-separable glasses described herein, theCu ions are less stable and may change to Cu²⁺ from Cu¹⁺.

The antimicrobial performance of the antimicrobial composite articles100 described herein can be influenced by the presence and thickness athin layer of the matrix 10 coincident with or over the second phaseparticles 20 on the exterior surface 40 (see FIGS. 1 and 1A). Dependingon the composition of the matrix 10 and its process history, this thinlayer may exhibit hydrophobic or substantially hydrophobic propertiesand may block the active copper species (Cu¹⁺) from exposure to air orfrom leaching to the exterior surface 40. For example, a matrix 10comprising a polymeric material that is hydrophobic or substantiallyhydrophobic (e.g., a polyolefin) can result in such a thin layer. In oneor more embodiments, the articles 100 may also use polymers as thematrix 10 that have balanced hydrophobic-hydrophilic properties thatfacilitate leaching of the active copper species. Examples of suchpolymers include hygroscopic/water soluble polymers and surfactants,amphiphilic polymers (e.g., poly(vinyl alcohol-co-ethylene)) and/or acombination of amphiphilic polymers and hygroscopic materials. In otherimplementations, the matrix 10 may comprise a polymeric material withsubstantially hydrophilic properties (e.g., poly(vinyl alcohol)).

In one or more embodiments, the exposure to air and/or leaching of theactive copper species to the surface may be facilitated by configuringthe articles 100 such that its exterior surface 40 (and, in some cases,exterior surfaces 30) with an “exposed portion”. As used herein, such an“exposed portion” is a portion of an exterior surface of theantimicrobial composite article 100 that has been mechanically and/orchemically treated to expose at least some of the second phase particles20 containing the phase-separable glass contained in the article 100(and surrounded by matrix 10) to the air or to provide some portion ofthe phase-separable glass at the exterior surfaces 30, 40 of thearticle. Specific methods for providing an exposed portion of anexterior surface include sanding, polishing, plasma treating (e.g., air,N₂, O₂, H₂, N₂ and/or Argon based plasma) and other methods that willremove a thin layer of the matrix 10 (e.g., a polymeric material). Inone or more alternative embodiments, the exposed portion of the exteriorsurfaces 30, 40 includes functional groups, particularly hydroxyl andcarbonyl groups, which are introduced into or to the exposed treatedsurface, to make such surface more hydrophilic. By providing an exposedportion of an exterior surface, the active copper species is exposed toair or more readily leaches the surface of the article 100.

To improve processing, mechanical properties and interactions betweenthe matrix 10 (e.g., a polymeric material) and the second phaseparticles 20 (e.g., phase-separable glass) described herein (includingany fillers and/or additives that may be used), processing agents/aidsmay be included in the antimicrobial composite articles 100 describedherein. Exemplary processing agents/aids can include solid or liquidmaterials. The processing agents/aids may provide various extrusionbenefits, and may include silicone based oil, wax and free flowingfluoropolymer. In other embodiments, the processing agents/aids mayinclude compatibilizers/coupling agents, e.g., organosilicon compoundssuch as organo-silanes/siloxanes that are typically used in processingof polymer composites for improving mechanical and thermal properties.Such compatibilizers/coupling agents can be used to surface modify theglass and can include (3-acryloxy-propyl)trimethoxysilane;N-(2-aminoethyl)-3-aminopropyltrimethoxysilane;3-aminopropyltri-ethoxysilane; 3-aminopropyltrimethoxysilane;(3-glycidoxypropyl)trimethoxysilane; 3-mercapto-propyltrimethoxysilane;3-methacryloxypropyltrimethoxysilane; and vinyltrimethoxysilane.

In some embodiments, the antimicrobial composite articles 100 describedherein may include fillers including pigments, that are typically metalbased inorganics can also be added for color and other purposes, e.g.,aluminum pigments, copper pigments, cobalt pigments, manganese pigments,iron pigments, titanium pigments, tin pigments, clay earth pigments(naturally formed iron oxides), carbon pigments, antimony pigments,barium pigments, and zinc pigments.

After combining the phase-separable glass described herein with a matrix10, as described herein, the combination may be formed into a desiredantimicrobial composite article 100. Examples of such articles 100include housings for electronic devices (e.g., mobile phones, smartphones, tablets, video players, information terminal devices, laptopcomputer, etc.), architectural structures (e.g., countertops or walls),appliances (e.g., cooktops, refrigerator and dishwasher doors, etc.),information displays (e.g., whiteboards), and automotive components(e.g., dashboard panels, windshields, window components, etc.).

In one or more embodiments, the articles 100 may exhibit desiredporosity and may be made into different shapes, including complex shapesand in different forms including plastics, rubbers and fiber/fabrics,which can have the same or different applications. Porous articles canalso be used as antimicrobial filters. For example, the articles may beextruded into a honeycomb structure, which not only includes channelsbut also porous channel walls.

In other embodiments, the articles 100 may include a high glass loadingassociated with the second phase particles 20. Such articles may beformed from a melting process or the wet process. In such embodiments,in addition to using the articles 100 themselves as an antimicrobialmaterial, the matrix 10 (e.g., a polymeric material) can be burnt out orremoved to (i.e., the article employs the matrix 10 as a fugitivematerial) provide a pure copper glass antimicrobial article that isporous, with a simple or complex shape.

Cu(I) is an excellent catalyst for organic reactions, particularly formild organic reactions, such as polymerization of acrylic monomers andoleochemical applications (e.g., hydrogenolysis of fatty esters to fattyalcohols including both methyl ester and wax ester processes, alkylationof alcohols with amines and amination of fatty alcohols), just to name afew. The antimicrobial composite articles 100 described herein may beused for such catalyst-oriented applications, even if not employed in anapplication that utilizes their inherent antimicrobial properties.

Referring to FIG. 1B, an energy dispersive spectroscopy (EDS) image ofphase-separable glass in an exterior surface of an antimicrobialcomposite article is provided according to an aspect of the disclosurethat is comparable to the antimicrobial composite article 100schematically depicted in FIG. 1. More specifically, the phase-separableglass in the EDS image in FIG. 1B is exemplary of the second phaseparticles 20 in an exposed portion of an exterior surface 40 (see FIG.1A). In FIG. 1B, the phase-separable glass was prepared according toU.S. patent application Ser. No. 14/623,077, filed on Feb. 16, 2015, thesalient portions of which related to phase-separable glass processingare hereby incorporated by reference within this disclosure. In FIG. 1B,the glass depicted in the EDS image is a phase-separable phosphate glassthat contains cuprite crystals (˜35 mol % cuprite) with a particle sizeof 100 to 250 nm in the discontinuous, low durability phase (i.e., thephosphate phase) and possesses a high antimicrobial efficacy. Inaddition, the phase-separable phosphate glass comprises carbon blackconcentrate for color (i.e., Clariant Corporation SL94620036 carbonblack). Further, the phase-separable glass depicted in FIG. 1B can bejet milled to a powder form and sieved (e.g., with a 325 mesh) to form aparticulate for use as second phase particles 20 in an antimicrobialcomposite article 100. The particulate can then be compounded with amatrix polymer (e.g., serving as matrix 10) to obtain the finalantimicrobial composite article form.

In an aspect of the disclosure, the foregoing antimicrobial compositearticle 100 containing the phase-separable glass depicted in FIG. 1B canbe compounded with polypropylene (serving as the matrix) with anextrusion process. For example, a Leistritz AG MIC18-7R GL twin-screwextruder can be employed for this process according to therepresentative conditions outlined below in Table 1. The extruder canthen be employed to produce the antimicrobial composite strip 100A (seeFIG. 2) without a carbon black colorant and a set of antimicrobialcomposite pellets 100B (see FIG. 2) with a carbon black colorant. Notethat the pellets 100B were obtained by a further processing of the stripobtained from the extruder.

TABLE ONE Extruder speed (RPM) 700 Zone 1 (° C.) 210 Zone 2 (° C.) 220Zone 3 (° C.) 225 Zone 4 (° C.) 230 Zone 5 (° C.) 235 Zone 6 (° C.) 240Die (° C.) 240 Melt Pressure (MPa) 1.4 Air Cooling Pressure (MPa) N/A

Referring to FIG. 3, an extruded antimicrobial composite form (e.g., thestrip and pellets of FIG. 2) can be injection molded or otherwiseprocessed into a sheet form as a coupon. In particular, FIG. 3 presentsphotographs of the antimicrobial composite coupons 100A′ and 100B′. Thecoupons 100A′ and 100B′ were prepared by injection molding theantimicrobial composite strip 100A and pellets 100B (see FIG. 2),respectively.

Referring again to FIG. 3, the antimicrobial composite coupons 100A′ and100B′ are 2.5 cm×2.5 cm square coupons suitable for antimicrobialefficacy testing with the Modified EPA Copper Test Protocol. Throughvarious antimicrobial efficacy tests conducted under the Modified EPACopper Test Protocol of coupons fabricated according to the foregoingantimicrobial composite article 100 forms, it was apparent that theas-fabricated composites can possess a thin layer of polymeric matrixmaterial at an exterior surface subject to such testing. Without beingbound by theory, it is believed that a thin layer of such matrixmaterial can prevent the copper in the phase-separable glass from beingeffectively exposed to the air and bacteria to obtain high antimicrobialefficacy. It is also believed, without being bound by theory, thatantimicrobial efficacy can depend on the degree of hydrophobicity (or,conversely, hydrophilicity) associated with the matrix material at anexterior surface subject to the testing. For example, such compositearticles having polymeric matrix materials that exhibit substantialhydrophobicity are prone to a scenario in which the bacteria (typicallyin an aqueous medium) does not uniformly spread across the exteriorsurface under test, resulting in lower than desired antimicrobialefficacy levels.

According to an aspect of the disclosure, exterior surfaces of theantimicrobial composite articles (e.g., exterior surface 40 of thearticle 100 depicted in FIGS. 1 and 1A) can be subjected to (a)mechanical removal of a thin layer of polymeric matrix material; and/or(b) surface chemistry modifications to introduce hydrophilic groups.With regard to the mechanical removal approach, hand sanding, gritblasting, polishing and other forms of material removal processes can beemployed on such exterior surfaces to expose a larger amount of thesurface area associated with the second phase particles containing thephase-separable glass with the copper-containing antimicrobial agent.Suitable approaches include hand sanding, e.g., with a 3M™ ContourSurface sanding sponge, to remove about 5 to 10 mg of material from theexterior surface of the antimicrobial composite article. The opticalmicrographs in FIG. 4 with a 350 micron scale demonstrate an exteriorsurface of an antimicrobial composite article with a polypropylenematrix and a phase-separable copper-containing glass before and aftersuch a hand sanding procedure. Another mechanical material removalapproach is sand blasting, e.g., with standard, known sand blastingequipment employing silica sand particulate. Typical sand blastingconditions employ sand at 0.1 to 0.5 MPa for 10 to 60 seconds ofexposure.

As for the surface modification approach, various techniques andprocesses may be employed to introduce hydrophilic groups on to theexterior surface 40 of the antimicrobial composite article 100. In oneaspect, the exterior surface 40 is subjected to a plasma treatment witha Nordson March Plasmod system. Such a system can be employed to plasmatreat the exterior surfaces of the antimicrobial composite articles,e.g., at 75 W for 8 min in an air or oxygen atmosphere. As shown in theoptical micrographs of FIG. 5, an exterior surface of an antimicrobialcomposite article with a polypropylene matrix and a phase-separablecopper-containing glass demonstrates a significant increase in wettingof an aqueous bacteria solution (e.g., as consistent withbacteria-containing media in the Modified EPA Copper Test Protocol)after such a plasma treatment step. In particular, the image on the leftside of FIG. 5 depicts an exterior surface of the composite articlewetted with the bacteria-containing solution before being subjected tothe plasma treatment. The image on the right depicts an exterior surfaceof the composite article wetted with the same bacteria-containingsolution after the surface had been subjected to a plasma treatment.

Without being bound by theory, it is believed that a combination of theforegoing mechanical material removal and surface chemistry modificationapproaches results in an exterior surface 40 of an antimicrobialcomposite article with very high antimicrobial efficacy levels, wellabove the levels that can be achieved by the use of either of techniquesalone. Moreover, the sequencing of these techniques does not appear toinfluence the final antimicrobial efficacy levels achieved by suchantimicrobial composite articles. Accordingly, an aspect of thedisclosure involves the combination of mechanical material removal andsurface chemistry modification to exterior surfaces of an antimicrobialcomposite article, conducted in either order.

According to an aspect of the disclosure, a method 200 of making anantimicrobial composite article 100 is provided, as shown in FIG. 6. Inparticular, the method includes a step 110 for providing a matrix (e.g.,matrix 10—see FIG. 1) comprising a polymeric material; and a step 120for providing a plurality of second phase particles (e.g., second phaseparticles 20) comprising an antimicrobial agent. Further, the method 200includes a step 130 for melting the matrix 10 to form a matrix melt.Next, the method 200 includes a step 140 for distributing the pluralityof second phase particles 20 in the matrix melt at a second phase volumefraction to form a composite melt; and a step 150 for forming acomposite article 60 from the composite melt. In addition, the method200 includes a final step 160 for treating the composite article 60 toform an antimicrobial composite article 100 having an exterior surface(e.g., exterior surface 40) comprising an exposed portion of the matrixand the plurality of second phase particles.

Referring again to FIG. 6, the step 170 of the method 200 of making anantimicrobial composite article 100 includes a step 170A for abrading(e.g., material removal from an exterior surface through mechanicalmeans) the composite article and a step 170B for plasma-treating thecomposite article 60, both steps conducted to develop the antimicrobialcomposite article 100. As shown in FIG. 6, steps 170A and 170B can beperformed in either order. According to a further aspect of the method200, step 170A for abrading the composite article can be used alone toform the antimicrobial composite article 100 for the specific situationin which the matrix material (e.g., matrix 10) primarily comprises ahydrophilic, polymeric material. As the matrix material is already in ahydrophilic state, it stands to reason the exterior surfaces of thecomposite article will also be hydrophilic in nature obviating the needfor a surface chemistry modification step such as step 170A.

In some aspects, the treating step 170 of the method 200 of making theantimicrobial composite article (see FIG. 6) can include abrading (e.g.,as in step 170A) the composite article 60 to form an antimicrobialcomposite article 100 having an exterior surface 40 comprising anexposed portion of the matrix 10 and the plurality of second phaseparticles 20. The abrading can be conducted with hand sanding, gritblasting or other similar grinding and/or polishing techniques. In otheraspects of the method, the treating step 170 can include abrading andplasma-treating (e.g., as in step 170B) the composite article 60 to forman antimicrobial composite article 100 having an exterior surface 40comprising an exposed portion of the matrix 10 and the plurality ofsecond phase particles 20. In these implementations, the abrading can beperformed before the plasma-treating or vice versa. Further, theplasma-treating can conducted with any of a variety of known processesthat produce or otherwise create functional groups in the exposedportion of the matrix on the exterior surface of the article.

According to some aspects of the method 200, the melting anddistributing steps 130 and 140, respectively, can include or otherwiseemploy an extrusion process. In addition, step 140 for distributing thesecond phase particles 20 in the matrix can be conducted with a meltprocess (e.g., compounding/extrusion and injection molding). Step 140can also be conducted with a solution process (e.g., adding the secondphase particles 20 into a coating with the matrix 10 material), a bulkpolymerization process and/or with a solution polymerization process(e.g., a suspension process or emulsion process for the second phaseparticles 20). Further, the step 150 for forming a composite article caninclude or otherwise employ an injection molding process. As such, theforming step 150 can be employed to fashion the composite article in afinal product form or a near net shape form.

In one aspect, the method 200 of making an antimicrobial compositearticle 100 can include the following steps: providing a matrixcomprising a hydrophobic polymeric material (e.g., step 110); providinga plurality of second phase particles comprising a copper-containingantimicrobial agent (e.g., step 120); melting the matrix to form amatrix melt (e.g., step 130); extruding the plurality of second phaseparticles in the matrix melt at a second phase volume fraction to form acomposite melt (e.g., step 140); injection molding a composite article(e.g., composite article 60) from the composite melt (e.g., step 150);and treating the composite article to form an antimicrobial compositearticle having an exterior surface comprising an exposed portion of thematrix and the plurality of second phase particles (e.g., step 170).Further, the exposed portion of the plurality of second phase particlesis distributed within the exposed portion of the matrix at a secondphase area fraction within 25% of the second phase volume fraction.

Referring to FIG. 7A, a bar chart depicts the antimicrobial efficacy (astested with the Modified EPA Copper Test Protocol) of antimicrobialcomposite articles having a polypropylene matrix and a plurality ofsecond phase particles comprising a phase-separable glass with acopper-containing antimicrobial agent, and subjected to various surfacetreatment steps. In FIG. 7A, the sample group designated “C” is acontrol sample of pure copper material. Sample groups “B1” through “B5”are indicative of antimicrobial composite articles subjected to varioussurface treatment steps—i.e., no treatment, plasma treatment in oxygen,plasma treatment in air, sand blasting, and hand sanding, respectively.As demonstrated by FIG. 7A, the various treatment steps conducted aloneon the antimicrobial composite articles provide little benefit in termsof antimicrobial efficacy as all such samples B1-B5 demonstrated a logkill of less 1 compared to the copper control sample C at a log kill of6.

FIG. 7B is a bar chart depicting the antimicrobial efficacy (as testedwith the Modified EPA Copper Test Protocol) of antimicrobial compositearticles having a polypropylene matrix and a plurality of second phaseparticles comprising a phase-separable glass with a copper-containingantimicrobial agent, and subjected to various surface treatment steps.In FIG. 7B, the sample group designated “C” is a control sample of purecopper material. Sample groups “A1” through “A3” are indicative ofantimicrobial composite articles subjected to various surface treatmentsteps—i.e., plasma treatment in oxygen and sand blasting, plasmatreatment in air and sand blasting, and hand sanding and plasmatreatment in air, respectively. As demonstrated by FIG. 7B, the varioustreatment steps conducted in combination on the antimicrobial compositearticles provide a significant benefit in terms of antimicrobialefficacy as all such samples A1, A2 and A3 demonstrated a log kill of 2or more.

FIGS. 8A & 8B are bar charts depicting the antimicrobial efficacy (astested with the Modified EPA Copper Test Protocol) of antimicrobialcomposite articles having a polysulfone matrix and a plurality of secondphase particles comprising a phase-separable glass with acopper-containing antimicrobial agent, and subjected to various surfacetreatment steps. In both FIGS. 8A & 8B, the sample group designated “C”is a control sample of pure copper material. In FIG. 8A, the samplegroup designated “A5” is indicative of an antimicrobial compositearticle subjected to plasma treatment and sanding process steps. In FIG.8B, the sample group designated “B6” is indicative of an antimicrobialcomposite article subjected to no surface treatments and the samplegroup designated “A4” is indicative of an antimicrobial compositearticle subjected to a hand sanding step followed by a plasma treatmentstep in air. As demonstrated by FIGS. 8A & 8B, antimicrobial compositearticles having a polysulfone matrix and a plurality of second phaseparticles comprising a phase-separable glass with a copper-containingantimicrobial agent can exhibit antimicrobial efficacy levels (i.e., logkill reductions of 3 or more) comparable or even exceeding similar suchantimicrobial composite articles employing a polypropylene matrix (see,e.g., FIGS. 7A & 7B).

Referring to FIG. 9, a bar chart depicts the antimicrobial efficacy (astested with the Modified EPA Copper Test Protocol) of antimicrobialcomposite articles having a polypropylene matrix and a plurality ofsecond phase particles comprising a phase-separable glass with acopper-containing antimicrobial agent, as subjected to various hospitalgrade cleaners. In FIG. 9, the sample group designated “C” is a controlsample of pure copper material. Sample groups “A6” through “A9” areindicative of antimicrobial composite articles subjected to a mechanicalsurface removal step (e.g., sanding) and a surface chemistrymodification step (e.g., plasma treatment in air), followed by noexposure to a hospital grade cleaner (A6) or exposure to varioushospital grade cleaners—i.e., 10% bleach (A7), Virex Tb (A8), andVesphene Ilse (A9). As demonstrated by FIG. 9, the exposure to thehospital cleaners cause no demonstrable reduction in the antimicrobialefficacy of these antimicrobial composite articles.

FIGS. 10A & 10B are bar charts depicting the antimicrobial efficacy (astested with the Modified EPA Copper Test Protocol) of antimicrobialcomposite articles having a polypropylene matrix and a plurality ofsecond phase particles comprising a phase-separable glass with acopper-containing antimicrobial agent, and subjected to variousenvironmental conditions. In both FIGS. 10A & 10B, the sample groupdesignated “C” is a control sample of pure copper material. In FIG. 10A,sample groups “A10” through “A13” are indicative of antimicrobialcomposite articles subjected to a mechanical surface removal step (e.g.,sanding) and a surface chemistry modification step (e.g., plasmatreatment in air), followed by no exposure to an environmental condition(A10) or exposure to various environmental conditions—i.e., 38° C./98%relative humidity for 24 hours (A11), 85° C./85% relative humidity for24 hours (A12), and 85° C./85% relative humidity for 7 days (A13).Similarly, in FIG. 10B, sample groups “A14” through “A19” are indicativeof antimicrobial composite articles subjected to a mechanical surfaceremoval step (e.g., sanding) and a surface chemistry modification step(e.g., plasma treatment in air), followed by no exposure to anenvironmental condition (A14) or exposure to various environmentalconditions—i.e., 38° C./98% relative humidity for 24 hours (A15), 4 days(A16), 7 days (A17), 10 days (A18), and 14 days (A19). As demonstratedby FIGS. 10A & 10B, the addition of the exposure of the antimicrobialcomposite articles to various environmental conditions involvingincreased temperature and humidity causes no demonstrable reduction inthe antimicrobial efficacy of these antimicrobial composite articles.

Referring to FIG. 11, a bar chart depicts the antimicrobial efficacy (astested with the Modified EPA Copper Test Protocol) of antimicrobialcomposite articles having a polypropylene matrix and a plurality ofsecond phase particles comprising a phase-separable glass with acopper-containing antimicrobial agent, with and without a subsequentfluorosilane layer over the exterior surfaces of the article. In FIG.11, the sample group designated “C” is a control sample of pure coppermaterial. Sample groups “A21” and “A22” are indicative of antimicrobialcomposite article subjected to a mechanical surface removal step (e.g.,sanding) and a surface chemistry modification step (e.g., plasmatreatment in air), followed by no additional coating (A21) or anadditional fluorosilane coating (A22), e.g., as configured forfingerprint, smudge resistance, scratch resistance or the like. Asdemonstrated by FIG. 11, the addition of the fluorosilane coating causesno demonstrable reduction in the antimicrobial efficacy of theseantimicrobial composite articles.

Aspect (1) of this disclosure pertains to an antimicrobial compositearticle, comprising: a matrix comprising a polymeric material; and aplurality of second phase particles comprising a phase-separable glasswith a copper-containing antimicrobial agent, wherein the plurality ofparticles is distributed within the matrix at a second phase volumefraction, and further wherein the composite article defines an exteriorsurface comprising an exposed portion of the matrix and the plurality ofthe second phase particles.

Aspect (2) of this disclosure pertains to the article of Aspect (1),wherein the exposed portion of the plurality of second phase particlesis distributed within the exposed portion of the matrix at a secondphase area fraction within 25% of the second phase volume fraction.

Aspect (3) of this disclosure pertains to the article of Aspect (1) orAspect (2), wherein the matrix comprises a polymeric materialcharacterized by substantial hydrophobicity, and further wherein theexposed portion of the matrix is characterized by substantialhydrophilicity.

Aspect (4) of this disclosure pertains to the article of any one ofAspect (1) through Aspect (3), wherein the polymeric material isselected from the group consisting of a polypropylene, a polyolefin anda polysulfone.

Aspect (5) of this disclosure pertains to the article of Aspect (1)through Aspect (4), wherein the phase-separable glass comprises at leastone of B₂O₃, P₂O₅ and R₂O, and the antimicrobial agent is cupritecomprising a plurality of Cu¹⁺ ions.

Aspect (6) of this disclosure pertains to the article of Aspect (1)through Aspect (5), wherein the exterior surface of the article exhibitsat least a log 2 reduction in a concentration of at least one ofStaphylococcus aureus, Enterobacter aerogenes, and Pseudomonasaeruginosa bacteria under a Modified EPA Copper Test Protocol.

Aspect (7) of this disclosure pertains to the article of Aspect (1)through Aspect (8), wherein the exterior surface of the article exhibitsat least a log 3 reduction in a concentration of at least one ofStaphylococcus aureus, Enterobacter aerogenes, and Pseudomonasaeruginosa bacteria under a Modified EPA Copper Test Protocol.

Aspect (8) of this disclosure pertains to the article of Aspect (5),wherein the plurality of second phase particles has a size distributiondefined by a 325 standard US mesh size.

Aspect (9) of this disclosure pertains to the article of Aspect (1)through Aspect (8), wherein the phase-separable glass comprises betweenabout 10 and 50 mol % cuprite.

Aspect (10) of this disclosure pertains to the article of Aspect (1)through Aspect (9), wherein the matrix comprises a polymeric materialcharacterized by substantial hydrophilicity.

Aspect (11) of this disclosure pertains to the article of Aspect (3),wherein the exposed portion of the matrix comprises functional groupsderived from a plasma treatment of the matrix.

Aspect (12) of this disclosure pertains to the article of Aspect (1)through Aspect (11), wherein the exterior surface of the compositearticle is configured as a high touch surface of an element selectedfrom the group consisting of a cover screen for a display device, ahousing for a display device, a counter-top, a table-top, a door knob, arail, and an elevator control panel.

Aspect (13) of this disclosure pertains to a method of making anantimicrobial composite article, comprising the steps: providing amatrix comprising a polymeric material; providing a plurality of secondphase particles comprising an antimicrobial agent; melting the matrix toform a matrix melt; distributing the plurality of second phase particlesin the matrix melt at a second phase volume fraction to form a compositemelt; forming a composite article from the composite melt; and treatingthe composite article to form an antimicrobial composite article havingan exterior surface comprising an exposed portion of the matrix and theplurality of second phase particles.

Aspect (14) of this disclosure pertains to the method of Aspect (13),wherein the matrix comprises a polymeric material characterized bysubstantial hydrophilicity.

Aspect (15) of this disclosure pertains to the method of Aspect (13) orAspect (14), wherein the treating step comprises abrading the compositearticle to form an antimicrobial composite article having an exteriorsurface comprising an exposed portion of the matrix and the plurality ofsecond phase particles.

Aspect (16) of this disclosure pertains to the method of Aspect (13)through Aspect (15), wherein the matrix comprises a polymeric materialcharacterized by substantial hydrophobicity, and further wherein theexposed portion of the matrix is characterized by substantialhydrophilicity.

Aspect (17) of this disclosure pertains to the method of Aspect (16),wherein the treating step comprises abrading and a plasma-treating thecomposite article to form an antimicrobial composite article having anexterior surface comprising an exposed portion of the matrix and theplurality of second phase particles.

Aspect (18) of this disclosure pertains to the method of Aspect (17),wherein the abrading is performed before the plasma-treating during thetreating step.

Aspect (19) of this disclosure pertains to the method of Aspect (17),wherein the plasma-treating is performed before the abrading during thetreating step.

Aspect (20) of this disclosure pertains to the method of any one ofAspect (13) through Aspect (19), wherein the polymeric material isselected from the group consisting of a polypropylene, a polyolefin anda polysulfone.

Aspect (21) of this disclosure pertains to the method of any one ofAspect (13) through Aspect (20), wherein the second phase particlesfurther comprise an SiO₂-containing glass and at least one of B₂O₃, P₂O₅and R₂O, and further wherein the antimicrobial agent is cupritecomprising a plurality of Cu¹⁺ ions.

Aspect (22) of this disclosure pertains to the method of any one ofAspect (13) through Aspect (21), wherein the melting and distributingsteps comprise an extrusion process and the forming a composite articlestep comprises an injection molding process.

Aspect (23) of this disclosure pertains to the method of any one ofAspect (13) through Aspect (22), wherein the exterior surface of theantimicrobial composite article exhibits at least a log 2 reduction in aconcentration of at least one of Staphylococcus aureus, Enterobacteraerogenes, and Pseudomonas aeruginosa bacteria under a Modified EPACopper Test Protocol.

Aspect (24) of this disclosure pertains to the method of any one ofAspect (13) through Aspect (23), wherein the exterior surface of theantimicrobial composite article exhibits at least a log 3 reduction in aconcentration of at least one of Staphylococcus aureus, Enterobacteraerogenes, and Pseudomonas aeruginosa bacteria under a Modified EPACopper Test Protocol.

Aspect (25) of this disclosure pertains to a method of making anantimicrobial composite article, comprising the steps: providing amatrix comprising a hydrophobic polymeric material; providing aplurality of second phase particles comprising an copper-containingantimicrobial agent; melting the matrix to form a matrix melt; extrudingthe plurality of second phase particles in the matrix melt at a secondphase volume fraction to form a composite melt; injection molding acomposite article from the composite melt; and treating the compositearticle to form an antimicrobial composite article having an exteriorsurface comprising an exposed portion of the matrix and the plurality ofsecond phase particles, wherein the exposed portion of the plurality ofsecond phase particles is distributed within the exposed portion of thematrix at a second phase area fraction within 25% of the second phasevolume fraction.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention.

What is claimed is:
 1. A method of making an antimicrobial compositearticle, comprising the steps: melting a matrix comprising a polymericmaterial to form a matrix melt; distributing a plurality of second phaseparticles comprising an antimicrobial agent in the matrix melt at asecond phase volume fraction to form a composite melt; forming acomposite article from the composite melt; and treating the compositearticle to form an antimicrobial composite article comprising anexterior surface comprising an exposed portion of the matrix and theplurality of second phase particles.
 2. The method of claim 1, whereinthe polymeric material of the matrix is characterized by substantialhydrophilicity, as measured by a contact angle between water and thepolymeric material of less than 90°.
 3. The method of claim 1, whereinthe treating step comprises abrading the composite article to form anantimicrobial composite article comprising an exterior surfacecomprising an exposed portion of the matrix and the plurality of secondphase particles.
 4. The method of claim 1, wherein the polymericmaterial of the matrix is characterized by substantial hydrophobicity,as measured by a contact angle between water and the polymeric materialof greater than 90°, and further wherein the exposed portion of thematrix is characterized by substantial hydrophilicity.
 5. The method ofclaim 4, wherein the treating step comprises abrading andplasma-treating the composite article to form the antimicrobialcomposite article having an exterior surface comprising an exposedportion of the matrix and the plurality of second phase particles. 6.The method of claim 5, wherein the abrading is performed before theplasma-treating during the treating step.
 7. The method of claim 5,wherein the plasma-treating is performed before the abrading during thetreating step.
 8. The method of claim 1, wherein the second phaseparticles comprise a phase-separated glass, and the antimicrobial agentcomprises a copper-containing antimicrobial agent.
 9. The method ofclaim 8, wherein the phase-separated glass comprises SiO₂ and at leastone of B₂O₃, P₂O₅, or R₂O, and wherein the copper-containingantimicrobial agent is cuprite comprising a plurality of Cu¹⁺ ions. 10.The method of claim 1, wherein the polymeric material is selected fromthe group consisting of a polypropylene, a polyolefin, and apolysulfone.
 11. The method of claim 1, wherein the melting anddistributing steps comprise an extrusion process, and the forming acomposite article step comprises an injection molding process.
 12. Themethod of claim 1, wherein the exterior surface of the antimicrobialcomposite article exhibits at least a log 2 reduction in a concentrationof at least one of Staphylococcus aureus, Enterobacter aerogenes, andPseudomonas aeruginosa bacteria under a Modified EPA Copper TestProtocol.
 13. The method of claim 1, wherein the exterior surface of theantimicrobial composite article exhibits at least a log 3 reduction in aconcentration of at least one of Staphylococcus aureus, Enterobacteraerogenes, and Pseudomonas aeruginosa bacteria under a Modified EPACopper Test Protocol.
 14. A method of making an antimicrobial compositearticle, comprising the steps: melting a matrix comprising a polymericmaterial to form a matrix melt; distributing a plurality of second phaseparticles comprising a phase-separated glass comprising acopper-containing antimicrobial agent in the matrix melt at a secondphase volume fraction to form a composite melt; forming a compositearticle from the composite melt; and treating the composite article toform an antimicrobial composite article comprising an exterior surfacecomprising an exposed portion of the matrix and the plurality of secondphase particles.
 15. The method of claim 14, wherein the treating stepcomprises abrading the composite article to form the antimicrobialcomposite article having an exterior surface comprising an exposedportion of the matrix and the plurality of second phase particles. 16.The method of claim 14, wherein the treating step comprisesplasma-treating the composite article to form the antimicrobialcomposite article having an exterior surface comprising an exposedportion of the matrix and the plurality of second phase particles. 17.The method of claim 14, wherein the treating step comprises abrading andplasma-treating the composite article to form the antimicrobialcomposite article having an exterior surface comprising an exposedportion of the matrix and the plurality of second phase particles. 18.The method of claim 14, wherein the phase-separated glass comprises SiO₂and at least one of B₂O₃, P₂O₅, or R₂O, and wherein thecopper-containing antimicrobial agent is cuprite comprising a pluralityof Cu¹⁺ ions.
 19. The method of claim 14, wherein the polymeric materialis selected from the group consisting of a polypropylene, a polyolefin,and a polysulfone.
 20. A method of making an antimicrobial compositearticle, comprising the steps: melting a matrix comprising a hydrophobicpolymeric material to form a matrix melt; extruding a plurality ofsecond phase particles comprising a copper-containing antimicrobialagent in the matrix melt at a second phase volume fraction to form acomposite melt; injection molding a composite article from the compositemelt; and treating the composite article to form an antimicrobialcomposite article comprising an exterior surface comprising an exposedportion of the matrix and the plurality of second phase particles,wherein the exposed portion of the plurality of second phase particlesis distributed within the exposed portion of the matrix at a secondphase area fraction within 25% of the second phase volume fraction.